title: An electrochemical immunosensor for sensitive detection of Escherichia coli O157:H7 using C60 based biocompatible platform and enzyme functionalized Pt nanochains tracing tag.
abstract: A sensitive and efficient electrochemical immunosensor was designed for amperometric detection of heat-killed Escherichia coli O157:H7 (E. coli O157:H7). The immunosensing platform was first composed of fullerene (C60), ferrocene (Fc) and thiolated chitosan (CHI-SH) composite nano-layer which could offer rich -SH functional groups and maintain good biocompatibility. Then the Au nanoparticles coated SiO2 nanocomposites (Au-SiO2) were assembled on the CHI-SH/Fc/C60 composite. Next, the large amount of avidin (SA) was coated on the Au-SiO2 surface, which was used to immobilize biotinylated capture antibodies of E. coli O157:H7 (bio-Ab1) through the covalent reaction between biotin and avidin. With surface area enhancement by C60 and Au-SiO2, and directional immobilization by avidin-biotin system, the amount of immobilized bio-Ab1 can be enhanced obviously. For signal amplification, the glucose oxidase (GOD) loaded Pt nanochains (PtNCs) were used as tracing tag to label signal antibodies (Ab2). With a sandwich-type immunoreaction, the concentration volume of heat-killed E. coli O157:H7 ranged from 3.2 × 10(1) to 3.2 × 10(6)CFU/mL with a limit of detection down to 15 CFU/mL (S/N=3), which could be well accepted for early clinical detection. The studied system provides new opportunities, and might speed up disease diagnosis, treatment and prevention with pathogen.
authors.affiliation: Department of Clinical Laboratory Science, College of Medical Laboratory, Southwest Hospital, Third Military Medical University, 30 Gaotanyan Street, Shapingba District, Chongqing 400038, PR China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Li
authors.forename: Lichao
authors.initials: L
authors.lastname: Fang
authors.forename: Ping
authors.initials: P
authors.lastname: Cheng
authors.forename: Jun
authors.initials: J
authors.lastname: Deng
authors.forename: Lili
authors.initials: L
authors.lastname: Jiang
authors.forename: Hui
authors.initials: H
authors.lastname: Huang
authors.forename: Junsong
authors.initials: J
authors.lastname: Zheng
mesh_terms: D055910:Antibodies, Immobilized / Q000737:chemistry; D015374:Biosensing Techniques / Q000295:instrumentation*; D048271:Chitosan / Q000031:analogs & derivatives; D055664:Electrochemical Techniques / Q000295:instrumentation; D004867:Equipment Design; D004927:Escherichia coli Infections / Q000175:diagnosis* / Q000382:microbiology; D019453:Escherichia coli O157 / Q000302:isolation & purification*; D005296:Ferrous Compounds / Q000737:chemistry; D037741:Fullerenes / Q000737:chemistry*; D006046:Gold / Q000737:chemistry; D006801:Humans; D007118:Immunoassay / Q000295:instrumentation; D000075163:Metallocenes; D008958:Models, Molecular; D053761:Nanocomposites / Q000737:chemistry*; D010984:Platinum / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry
chemical_list: D055910:Antibodies, Immobilized; D005296:Ferrous Compounds; D037741:Fullerenes; D000075163:Metallocenes; D010984:Platinum; D006046:Gold; D012822:Silicon Dioxide; D048271:Chitosan; C069837:fullerene C60; C004998:ferrocene
keywords: Au nanoparticles coated SiO(2) nanocomposites; Escherichia coli O157:H7; Fullerene; Immunosensor; Pt nanochains